1. Field of the Invention:
This invention relates to a synchronous KVAR regulation system connected to a power distribution line to generate capacitive KVARS to automatically follow and compensate for the inductive KVARS being generated by other loads on the distribution line.
2. Description of the Prior Art
In many industrial applications, a serious problem is the a.c. power line variations during normal manufacturing operations which are the result of fluctuating demands. These system line voltage swings are the result of variations in both real and reactive power demands. The fluctuating real power demand results from energy expended during the manufacturing process and little can be done about it. The variation in KVAR (reactive power) demand can however be compensated for, at least in part. Additionally, many utilities bill the industrial customer based on both a 15 or 30 minute kilowatt demand during the month as well as on a maxiumum 15 or 30 minute KVAR demand. Obviously anything the customer can do to improve the KVAR demand will lower the cost of energy.
In most applications, the industrial loads create lagging (inductive) demands. It is known in the art that an overexcited synchronous motor will generate corrective (capacitive) KVARS to compensate for the lagging KVARS. The use of the synchronous motor to improve line voltage and power factor is discussed at length in a paper "Use of Synchronous Motor Drives for Maintaining Distribution System Line Voltage and Power Factor" by Robert S. Peterson IEEE Transitions on Industry and General Applications Vol. IGA-7, No. 6, November/December 1971.
The present invention provides a synchronous motor KVAR regulation system utilizing a synchronous motor to provide corrective (capacitive) KVARS while at the same time providing for thermal and synchronization protection.